Standard optical encoder systems use two or three optical sensors with a counting mechanism to track a linear or rotational position of a monitored subject. Optical encoders have been employed in autonomous vehicle for rotational and/or linear position of various (driving control units). These systems, however, comprise mostly analog components and the incorporation of traditional encoders require the control/object monitored to be disassembled or completely redesigned to incorporate an encoder. Thus, they are limited as to the locations they can be mounted on, in an environment that is densely populated with control tools and electronics such as the driving control area of an autonomous vehicle. Further, the processing speed of such an analog system is significantly slower compared to a fully digitized system. Therefore, a need exists for improved accuracy and speed of sensing.
An ability to get more information about the rotational and/or linear position of different driving control units from different optical encoders, strategically placed proximal to the driving control units, improves the reliability of the sensing system. The driving control area is typically an environment that is densely populated with control systems and electronics and has limited wiring provisions available. Therefore, a need exists for a network for encoder systems and communications techniques between the network of encoder systems and a processing unit within the limited wiring options.
High-speed, real-time sensing systems that involve counting, a common scenario with optical encoder systems, may sometimes lead to spurious data due to a lag or a noise interference between a sensed change of value and the corresponding count value. In bidirectional counting systems, in situations where the sensed value changes back and forth between two subsequent positions, this lag or noise interference may lead to erroneous unidirectional counting, completely bypassing a reversal in counting direction that must have occurred. This can lead to a dysfunctional system. Therefore, a need exists to ensure timely transition between the counting directions for the successful and reliable operation of the system.
Autonomous vehicles typically have lengthy electrical connection buses connecting sensing systems and processing units that are often separated by a significant physical distance. The Signal to Noise Ratio (SNR) of high-speed digital signals deteriorates with increased wire length due to increased noise interferences and bus capacitances. Therefore, a need exists for translating the high-speed signal into a signal suitable for distant communication.
Therefore, a need exists for a compact, high-speed, digital optical encoder system which can be conveniently mounted and networked with a large number of other such systems, for improved sensing performance, and be held in communication with a processing unit that is separated by a physical distance with a sufficient signal quality.